A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Colloidal
Solution
Colloidal
solution is a heterogeneous two phase system. One phase consists of dispersed
particles of colloidal range and is called dispersed phase. The other phase
comprising the medium in which the colloidal particles are dispersed is called
dispersion medium.
Color
An attribute of
things that causes visual sensation which results from light rays reflection,
transmission or emission. The visual sensation depends on its wavelength.
Color
Center
Insulators that
are transparent because of large band gap appear colored some times. This color
results from selective absorption of some portion of the visible spectrum by
imperfections in crystal. Such imperfections in a crystal which selectively
absorbs certain colors in visible spectrum are called color centers. Alkali
halide crystals when doped with transition element ions or the ions whose salts
are normally colored creates color centers in those crystals.
Coma
The rays of light
passing through the marginal zones of a convex lens converge nearer to the lens
as compared to the paraxial rays because the local length of the lens is less
for the marginal rays and large for paraxial rays. For an object highly off
principal axis, the images forced by different zones of convex lens are piled
on the top of the other in the direction perpendicular to the principal
axis. This transverse displacement of
images due to variation of local length of local zones is known as Coma.
Combined
Inversion (CP)
“Landau” advanced
a hypothesis that any physical interaction must be invariant under simultaneous
reversal of position coordinates and change over from particles to
antiparticles.
Comet
A celestial body
containing ice and dust, and has highly eccentric orbit.
Compass
Device used to
determine geographical direction usually consisting of a magnetic needle
mounted on a pivot itself naturally with the earth’s magnetic field so that it
points to earth’s magnetic north or South Pole.
Compensated
Neutron Ionization Chamber
By the word
“compensated”, we mean compensating the response of neutron detector to gamma
rays. Compensated ionization chambers consist of two separate chambers; one
chamber is coated with Boron-10 isotope, and one chamber without any coating.
The coated chamber is sensitive to both gamma rays and neutrons, while the
uncoated chamber is sensitive only to gamma rays. Instead of having two separate
ammeters and subtracting the currents, the subtraction of these currents is
done electrically and the net output of both detectors is read on a single
ammeter. If the polarities are arranged so that the two chambers’ currents
oppose one another, the reading obtained from the ammeter indicates the
difference between the two currents. One plate of the compensated ion chamber
is common to both chambers; one side is coated with boron, while the other side
is not. The boron coated chamber is referred to as the working chamber; the
uncoated chamber is called the compensating chamber. When exposed to a gamma
source, the battery for the working chamber will set up a current flow that
deflects the meter in one direction. The compensating chamber battery will set
up a current flow that deflects the meter in the opposite direction. If both
chambers are identical and both batteries are of the same voltage, the net
current flow is exactly zero. Therefore, the compensating chamber cancels the
current due to gamma rays.
Compensated
Pendulum
A clock pendulum in which the effect of changes of
temperature of length of the rod is so counteracted, usually by the opposite
expansion of different metals, that the distance of centre of oscillation from
centre of suspension remains invariable.
Complex
number
If you pair a
real number with an imaginary number we get complex number, which can be
plotted on two dimensional plane. It is of the form a + ib; where ‘a’ is any
whole number and ‘ib’ is imaginary part.
Composite
Radionuclide
A composite radio
nuclide is the one that contains more than one radioisotope at the same time.
Most of the radioactive materials found in nature are composite radio nuclide.
Composition
The relative
content of a particular element or constituent within an alloy, usually
expressed in weight percent or atom percent.
Compound
Lens
It is an optical device which is an array
of simple lenses on a common axis; for correcting optical aberrations.
Compound
Microscope
A compound microscope uses two lenses, one
with very short focal length to form enlarged image; the second one is a short
focal length eye piece to magnify the enlarged image.
Compound
Nucleus
It is an unstable nucleus which is formed when energetic particles coalesces with nucleus. The energy brought in by incident particle is shared among degrees of freedom of compound nucleus. When one or more nuclear particles acquire energy that is greater than the average binding energy, then such particles leave the nucleus. The concept was first advanced by
N. Bohr in 1936.
